1. Resignation is not an option
2. If your analog filters are sharper, then they are slow, which can mean something like 100ms perhaps. You may not have noted this because incandescent lamps are slow in the first place.
3. Some instruments DO cover a large part of the spectrum, snares etc. certainly do.
4. I agree that one does not want to constantly tweak the preset with the music, although definitely a decent DJ should select presets fitting to the music.
5. You can do much more exciting things with MD than simple flickering lights. I personally prefer making presets a lot over using them, but that is of course a personal attitude.
6. Technically what contributes to the apparently better frequency separation of your light bulbs is probably their nonlinear response. Light bulbs will hardly start even glowing when operated below 1/3 of their rated voltage, plus they are much slower in the low voltage range. Their brightness is proportional to something like the square of the voltage, or possible even the third power. Attached a sample of how you might simulate this in MD. Not all steps may be required.